Hi, I just bought a used 08 135i this weekend, and am experiencing the sloppy feel that everyone is talking about.

I was wondering ... if I only upgraded the M3 Sway Bar, and M3 front control arms (tension strut, control arm, headlight adj rod), will it be sufficient to eliminate the issue? I do not wish to install coilovers at this time.

This is because I currently have a full set of suspension upgrades on my 335i. It's relatively cheap to purchase a 2nd M3 sway bar & control arm kit for the 135i, but I'm trying not to spend money on a 2nd coilover set. I will turn the 335i back into a family car in the future, but am not ready to swap the coilovers over to the 135i just yet.

Coming from the 335i with full suspension upgrades + LSD, you can imagine how much the sloppy feeling bothers me!

Hi, I just bought a used 08 135i this weekend, and am experiencing the sloppy feel that everyone is talking about.

I was wondering ... if I only upgraded the M3 Sway Bar, and M3 front control arms (tension strut, control arm, headlight adj rod), will it be sufficient to eliminate the issue? I do not wish to install coilovers at this time.

This is because I currently have a full set of suspension upgrades on my 335i. It's relatively cheap to purchase a 2nd M3 sway bar & control arm kit for the 135i, but I'm trying not to spend money on a 2nd coilover set. I will turn the 335i back into a family car in the future, but am not ready to swap the coilovers over to the 135i just yet.

Coming from the 335i with full suspension upgrades + LSD, you can imagine how much the sloppy feeling bothers me!

Thanks!

Which sloppy feeling are you referring to?

If the body roll: M3 front roll bar
If steering is sloppy: M3 control arms + wishbones
If the rear feels like the subframe and the car aren't moving as one: rear subframe bushings (this is an important one)
If it's sloppy coming out of corners: M3 Rear links (upper + toe arm)

I'd do all of those before considering upgrading to coilovers or new springs/shocks. You won't get the full benefit of upgrading the springs/shocks unless parts move up and down correctly.

I think that most of the slop in daily driving is due to the sub frame bushings. I would do them first. Then bars and such when you switch to coil overs. I installed coil overs before the bushings and could still feel plenty of slop in daily driving. After the bushings, much more solid.

Can someone explain to me this notion that is so popular in this forum that the front m3 anti-roll bar upgrade is a good one? And can they please describe for me in detail what the effects of this are and how they are desireable?

The M3 E93 is a 28mm thick sway bar with a top-quality stiff bushings and alloy fitting brackets instead of standard (including M-Sport) 26,5mm one with a jelly-soft bushings and a steel brackets.

The effect is in elimination of the suspension noise when passing road cracks and bumps (especially feels on the railway crossing is you have the in-city ones), and flat cornering with a fast and accurate reaction to the steering adding inside of the corner.

Best when used with at least straight M3 front control arms- their stiffer bushings totally delete the suspension hits and rattling, and the approximately 1cm bigger length increases camber from 0.6 to 1.1 degree which reduces understeering with no negative effect.

Best when used with at least straight M3 front control arms- their stiffer bushings totally delete the suspension hits and rattling, and the approximately 1cm bigger length increases camber from 0.6 to 1.1 degree which reduces understeering with no negative effect.

I keep reading about the use of M3 front control arms for the stiffer bushings and the increased camber. But what if you already have a good camber angle (with the help of camber plates)? Is it worth upgrading the whole control arm just for the bushing? Or could I just swap out the bushing and get the full effect?

Also, a lot of places sell the control arms in a package with the wishbones. Is there much benefit to spending the extra $200ish for the wishbones?

Harold explains it here. He doesn't mention that it's an effect of MacPherson struts, so I'll add that from another source.

Quote:

several problems can occur when a car heels way over in a turn. First, the suspension can gain positive camber. This is worse in cars with MacPherson strut suspensions. With strut-type suspensions, the car rolls, but the tires don't. This forces the tire to roll onto its outside edge and reduces its contact patch-clearly not the best way to use the tire. http://www.modified.com/tech/0506_sc...1/viewall.html

Quote:

Originally Posted by HP Autowerks

Most would think adding a large front antil roll bar would typically increase understeer. They are only partially right, but what they didn't know is why the vehicle understeer in the first place.

There are situations where increasing the the stiffness of the front anti roll bar will have the opposite affect and actually reduce understeer.

Here is why:

If you have a vehicle with so much body roll, which induces so much camber change(excess positive camber), your outside front tire is almost riding or is on its sidewalls(in extreme cases), you are losing tracting from the lack of contact patch.

By reducing the body roll-induced camber change(using larger from anti roll bar). With the tires rolling over much less and in more direct/flat contact with the road, more traction is created.

Ah, yes this is true, but adding front spring also increases understeer by loading the outiside front more than the outisde rear. This is why I asked if he thought it was replacing one source of understeer for another?

Sure it has to, so what compromise is fastest? You can only know by testing them on a track.

Thanks for everyone's input. It's been a few days and 300 miles since I bought the car (89K miles on it), and I now have a better description of 'sloppy'.

Basically, when I was first getting used to the car, there was a lot of body movement while driving on regular roads. The periodic imperfections present on all roads causes a MINOR left to right unsettling motion (in addition to the normal up and down travel), that when factored over a course of a daily commute, was enough to give me a little motion sickness.

It's been a couple hundred miles now, and my body has since adapted (no longer feel the motion sickness), but I still want to correct this feeling. Based on your input, it seems like worn rear subframe bushings are the main culprit?

Question 1: How much labor (hrs) should my mechanic charge to replace the rear subframe bushings? While I'm at it, what other upgrades can I do to save on labor?

Question 2: Do I have to change the front subframe bushings too? What's the estimated labor hours?

Question 3: What are the total sum of all types of bushings in the car that will eventually wear and affect ride comfort and handling?

a) Sub-frame bushings (front + rear) - alignment needed?
b) Sway Bar bushings? (might as well upgrade to the M3 sway bar)
c) Control Arm bushings? (a reason for the M3 control arm kit upgrade)
d) Anything else? I thought the sway bar connects to the tie rod ends or something, and those have bushings? Or is that part of the M3 sway bar kit?

Q1: Plan on 6-8 hours for the rear subframe bushings. Make sure the mechanic has performed the swap and has the tool necessary to remove/install the bushings. HP Autowerks rents the tool if your mechanic does not have one. In order to swap the bushings, the rear subframe is removed from the frame. This requires that the rear brake lines need to be removed. There are actually four rear brake lines. Two mid-rear lines and two rear-rear lines. If you ever plan on installing new brake lines, do it know. The mid-rear lines are a complete PITA to replace without lowering the subframe. Also, if you plan on upgrading to the M3 rear sway bar, do it know. Most people would not recommend this upgrade (especially if you have an open differential).

Q2: I do not believe that there are similar front subframe bushings, and I have never heard of anyone changing them... I could be wrong... I've never looked. I believe the comment regarding front subframe bushings was in reference to the front two bushings in the rear subframe (there's a total of four bushings in the rear).

Q3: There are countless bushing that could impact the ride quality/accuracy but you nailed the most important ones.

Keep in mind that anytime you change suspension components it's a good idea to get a proper alignment. Only possible exception is the front sway bar. If you upgrade to the M3 control arms, you MUST get an alignment. And if you need to drive the car to the alignment shop, be careful! Controlling the car will be a handful.

Huh? I googled that and I see info about the manual transmission clutch....

Test drove a E46 330CI and a E90 325i and it makes me appreciate the steering in the 135i even more, definitely much better than the older models, although the cars were much older, so not sure how much was wear and tear on the steering components.

Huh? I googled that and I see info about the manual transmission clutch....

Test drove a E46 330CI and a E90 325i and it makes me appreciate the steering in the 135i even more, definitely much better than the older models, although the cars were much older, so not sure how much was wear and tear on the steering components.

Apologies. Responded too quickly thinking this thread was was about the sloppy shifts.

One thing that addressed the floating sensation coming from the rear of my 135i is the replacement of the stock subframe bushings. These are so soft that you can squeeze them in you hands. Try this when you are ever under your car - the subframe can be moved with a light force from a large screwdriver or crowbar.

Easy and cheapest way to address this is with buhings inserts that will fill the voids in your stock bushings.

Best way is replacement with M3 bushings, but the rear subframe has to be loosened, and driver side brake lines detached.

The stock front control arms can be replaced with the M3 ones as well, which have sturdier bushings, and provide about -0.7* of negative camber. Both of these features help with turn in and steering preciseness.

Did this to my 135i which I take to track, and it helped a lot. Big positive impact to car behavior on the street as well...